Conventionally a plastic eraser has been usually produced by adding a plasticizer, and if needed, other additives such as a stabilizer and a colorant, to a base resin to prepare a uniform mixture, and heating and molding the mixture using a suitable molding means.
In such a conventional plastic eraser as mentioned above, a vinyl chloride resin is most widely used as a base resin, and a phthalate ester plasticizer such as dioctyl phthalate and dibenzyl phthalate is most widely used as a plasticizer.
However, in recent years, it is pointed out that such a phthalate ester plasticizer as mentioned above has a possibility that it would act as the so-called environmental hormone (endocrine disruptors). Such being the case, a new plasticizer for the plastic eraser which would replace the conventional phthalate ester plasticizer is demanded.
Thus, for example, a plastic eraser has been proposed which uses such a non-phthalate ester plasticizer as acetyltributyl citrate (see Patent Document 1), 4,5-epoxy-1,2-cyclohexanedicarboxylic acid bis(2-ethylhexyl) (see Patent Document 2), sebacic acid diester (see Patent Document 3), and an alkylsulfonic acid phenyl ester (see Patent Document 4).
Furthermore, in a plastic eraser which uses urethane resin as a base resin, the use of combination of non-phthalate ester plasticizers such as 4,5-epoxy-1,2-cyclohexanedicarboxylic acid bis(2-ethylhexyl) and a dialkylene glycol benzoate is also proposed (see Patent Document 5).
A plastic eraser composite body is also proposed in recent years. The plastic eraser composite body comprises a porous structure formed of an organic polymer and having pores therein, and a plastic eraser contained in the pores. When writings provided on the surface of paper are rubbed and erased with the plastic eraser composite body, the eraser is worn on the surface of the paper while the skeletal structure of the porous structure is also broken on the surface of the eraser at which it is worn, thereby it is superior not only in erasing performance but also in eraser scraps integrating property (see Patent Document 6).
However, as to a plastic eraser which comprises a vinyl chloride resin as a base resin, there has not yet been proposed any non-phthalate ester plasticizer which is effective from the viewpoint of reduction of environmental load and improvement in erasing performance.